Asymmetric dialdimine-containing polyurethane composition

ABSTRACT

The invention relates to moisture-curing compositions which comprise at least one aromatic isocyanate group-bearing polyisocyanate and at least one dialdimine of formula (I). The compositions according to the invention have a longer open time and at the same time a shorter curing time, they are storage-stable and cure without forming bubbles. They are especially suitable as adhesives, sealing agents, potting compounds or coating materials, the use as sealing agents being especially advantageous.

This is a Division of application Ser. No. 12/450,180 filed Sep. 15,2009, which in turn is National Stage Application of PCT/EP2008/053635,filed on Mar. 27, 2008, which claims the benefit of European PatentApplication No. 07105006.6 filed Mar. 27, 2007. The disclosure of theprior applications is hereby incorporated by reference herein in itsentirety.

TECHNICAL FIELD

The present invention relates to the field of moisture-curingpolyurethane compositions, and to the use thereof, especially as elasticadhesives, sealants and coatings.

STATE OF THE ART

Moisture-curing compositions based on polyurethane polymers havingisocyanate groups have been used for some time as elastic adhesives,sealants and coatings. The polyurethane polymers used therein aretypically formed from polyetherpolyols and polyisocyanates. When theyare cured by means of moisture, these compositions tend to form bubblesas a result of carbon dioxide gas released, which is not dissolved orled off rapidly enough.

In order to prevent bubble formation, capped amines, so-called “latenthardeners”, for example polyoxazolidines, polyketimines orpolyaldimines, can be added to the polyurethane compositions. This can,however, lower the storage stability of the compositions.

U.S. Pat. No. 4,469,831 and U.S. Pat. No. 4,853,454 disclosepolyurethane compositions which comprise polyaldimines and which possessa good storage stability.

WO 2004/013200 discloses polyurethane compositions comprising specificpolyaldimines, which likewise have a good storage stability and whichcure without odor.

Polyurethane compositions comprising latent hardeners, especially thosebased on aromatic polyisocyanates, however, usually have thedisadvantage that their curing sets in very rapidly, so as to give riseto too short an open time and hence too short a processing window.Moreover, in the course of curing, usually volatile and odorouselimination products, especially aldehydes or ketones, are released,which is troublesome or completely undesired according to theapplication.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to providemoisture-curing polyurethane compositions which are storage-stable, havea long open time and a high curing rate, and cure without bubbleformation.

It has now been found that, surprisingly, compositions as claimed inclaim 1 solve this problem. These compositions comprise specificasymmetric dialdimines, as a result of which they are simultaneouslystorage-stable, have a long open time and a high curing rate, and curewithout bubbles. In a preferred embodiment, these compositions areadditionally odorless, before, during and after their curing. Thecompositions may have a one-component or two-component configuration,and be used as an adhesive, sealant, potting composition or coating. Aparticularly advantageous use has been found to be that as a sealant.

The invention further provides a process for adhesive bonding asdescribed herein, a process for sealing as described herein and aprocess for coating as described herein.

Finally, the cured composition as described herein and the articlesadhesive bonded, sealed or coated by the processes described asdescribed herein form part of the subject matter of the presentinvention.

Preferred embodiments of the invention are also described herein.

Ways of Performing the Invention

The present invention provides a composition comprising

-   -   a) at least one polyisocyanate P having aromatic isocyanate        groups, and    -   b) at least one dialdimine A of the formula (I).

In this structure, X is the radical of a diamine DA with two primaryamino groups after the removal of these two amine groups. In addition,Y¹ and Y² are either each independently a monovalent hydrocarbon radicalhaving 1 to 12 carbon atoms, or Y¹ and Y² together are a divalenthydrocarbon radical which has 4 to 20 carbon atoms and is part of anoptionally substituted carbocyclic ring having 5 to 8, preferably 6,carbon atoms.

In addition, Y³ is a monovalent hydrocarbon radical which optionally hasat least one heteroatom, especially oxygen in the form of ether,carbonyl or ester groups.

An essential proviso for the invention is that at least one of the twoprimary amino groups of the diamine DA is an aliphatic amino group, andthat the two primary amino groups of the diamine DA differ from oneanother either

-   -   in the number of hydrogen atoms on the carbon atoms (C_(α)) in        the α position to the particular amino group by at least one

or

-   -   in the number of hydrogen atoms on the carbon atoms (C_(β)) in        the β position to the particular amino group by at least two.

In the present document, the term “polymer” firstly embraces acollective of macromolecules which are chemically homogeneous butdifferent in relation to degree of polymerization, molar mass and chainlength, which has been prepared by a poly reaction (polymerization,polyaddition, polycondensation). The term secondly also embracesderivatives of such a collective of macromolecules from poly reactions,i.e. compounds which have been obtained by reactions, for exampleadditions or substitutions, of functional groups on givenmacromolecules, and which may be chemically homogeneous or chemicallyinhomogeneous. The term further also comprises what are known asprepolymers, i.e. reactive oligomeric preliminary adducts whosefunctional groups are involved in the formation of macromolecules.

The term “polyurethane polymer” embraces all polymers prepared by whatis known as the diisocyanate polyaddition process. This also includesthose polymers which are virtually or entirely free of urethane groups.Examples of polyurethane polymers are polyetherpolyurethanes,polyesterpolyurethanes, polyetherpolyureas, polyureas,polyesterpolyureas, polyisocyanurates and polycarbodiimides.

In the present document, substance names beginning with “poly”, such aspolyaldimine, polyisocyanate, polyol or polyamine, denote substanceswhich, in a formal sense, contain two or more of the functional groupswhich occur in their name per molecule.

In the present document, the term “aromatic isocyanate group” refers toan isocyanate group which is bonded to an aromatic carbon atom.

In the present document, the term “primary amino group” refers to an NH₂group which is bonded to an organic radical, whereas the term “secondaryamino group” refers to an NH group which is bonded to two organicradicals which may also together be part of a ring.

“Aliphatic amino group” refers to an amino group which is bonded to analiphatic, cycloaliphatic or arylaliphatic radical. It thus differs froman “aromatic amino group”, which is bonded directly to an aromatic orheteroaromatic radical, as, for example, in aniline or 2-aminopyridine.

In this document, “open time” refers to the time during which thecomposition can be processed once the isocyanate groups of thepolyisocyanate have come into contact with water.

The composition comprises at least one polyisocyanate P having aromaticisocyanate groups.

In a first embodiment, the polyisocyanate P having aromatic isocyanategroups is a polyurethane polymer PUP having aromatic isocyanate groups.

A suitable polyurethane polymer PUP is especially obtainable from thereaction of at least one polyol with at least one aromaticpolyisocyanate. This reaction can be effected by reacting the polyol andthe polyisocyanate by customary methods, for example at temperatures of50° C. to 100° C., optionally with additional use of suitable catalysts,the polyisocyanate being metered in such a way that its isocyanategroups are present in a stoichiometric excess in relation to thehydroxyl groups of the polyol. The polyisocyanate is advantageouslymetered in so as to observe an NCO/OH ratio of 1.3 to 5, especially oneof 1.5 to 3. The NCO/OH ratio is understood here to mean the ratio ofthe number of the isocyanate groups used to the number of the hydroxylgroups used. Preferably, in the polyurethane polymer PUP after thereaction of all hydroxyl groups of the polyol, there preferably remainsa content of free isocyanate groups of 0.5 to 15% by weight, morepreferably of 0.5 to 10% by weight.

Optionally, the polyurethane polymer PUP can be prepared with additionaluse of plasticizers, in which case the plasticizers used do not containany groups reactive toward isocyanates.

The polyols used for the preparation of a polyurethane polymer PUP may,for example, be the following commercial polyols or mixtures thereof.

-   -   Polyoxyalkylenepolyols, also known as polyetherpolyols or        oligoetherols, which are polymerization products of ethylene        oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, oxetane,        tetrahydrofuran or mixtures thereof, possibly polymerized with        the aid of a starter molecule with two or more active hydrogen        atoms, for example water, ammonia or compounds having a        plurality of OH or NH groups, for example 1,2-ethanediol, 1,2-        and 1,3-propanediol, neopentyl glycol, diethylene glycol,        triethylene glycol, the isomeric dipropylene glycols and        tripropylene glycols, the isomeric butanediols, pentanediols,        hexanediols, heptanediols, octanediols, nonanediols,        decanediols, undecanediols, 1,3- and 1,4-cyclohexanedimethanol,        bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane,        1,1,1-trimethylolpropane, glycerol, aniline, and mixtures of the        aforementioned compounds. It is possible to use either        polyoxyalkylenepolyols which have a low degree of unsaturation        (measured to ASTM D-2849-69 and reported in milliequivalents of        unsaturation per gram of polyol (meq/g)), prepared, for example,        with the aid of double metal cyanide complex catalysts (DMC        catalysts), or polyoxyalkylenepolyols with a higher degree of        unsaturation, prepared, for example, with the aid of anionic        catalysts such as NaOH, KOH, CsOH or alkali metal alkoxides.

Particularly suitable are polyoxyalkylenediols and -triols, especiallypolyoxypropylenediols and polyoxypropylenetriols.

Especially suitable are polyoxypropylenediols and -triols having adegree of unsaturation lower than 0.02 meq/g and a molecular weight inthe range of 1000-30 000 g/mol, and also polyoxypropylenediols and-triols with a molecular weight of 400-8000 g/mol.

Likewise particularly suitable are so-called ethylene oxide-terminated(“EO-endcapped”, ethylene oxide-endcapped) polyoxypropylenepolyols. Thelatter are specific polyoxypropylenepolyoxyethylenepolyols which areobtained, for example, by further alkoxylating purepolyoxypropylenepolyols, especially polyoxypropylenediols and -triols,with ethylene oxide on completion of the polypropoxylation reaction, andhave primary hydroxyl groups as a result,

-   -   Styrene-acrylonitrile- or acrylonitrile-methyl        methacrylate-grafted polyetherpolyols.    -   Polyesterpolyols, also known as oligoesterols, prepared, for        example, from di- to trihydric alcohols, for example        1,2-ethanediol, diethylene glycol, 1,2-propanediol, dipropylene        glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,        neopentyl glycol, glycerol, 1,1,1-trimethylolpropane or mixtures        of the aforementioned alcohols, with organic dicarboxylic acids        or the anhydrides or esters thereof, for example succinic acid,        glutaric acid, adipic acid, suberic acid, sebacic acid,        dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic        acid, isophthalic acid, terephthalic acid and hexahydrophthalic        acid, or mixtures of the aforementioned acids, and also        polyesterpolyols formed from lactones, for example from        ε-caprolactone.    -   Polycarbonatepolyols, as obtainable by reaction, for example, of        the abovementioned alcohols—used to form the        polyesterpolyols—with dialkyl carbonates, diaryl carbonates or        phosgene.    -   Polyacrylate- and polymethacrylatepolyols.    -   Poly-hydroxy-functional fats and oils, for example natural fats        and oils, especially castor oil; or polyols—known as        oleochemical polyols—obtained by chemical modification of        natural fats and oils, for example the epoxy polyesters or epoxy        polyethers obtained by epoxidation of unsaturated oils and        subsequent ring opening with carboxylic acids or alcohols, or        polyols obtained by hydroformylation and hydrogenation of        unsaturated oils; or polyols obtained from natural fats and oils        by degradation processes such as alcoholysis or ozonolysis and        subsequent chemical linkage, for example by transesterification        or dimerization, of the degradation products or derivatives        thereof thus obtained. Suitable degradation products of natural        fats and oils are especially fatty acids and fatty alcohols, and        also fatty acid esters, especially the methyl esters (FAME),        which can be derivatized, for example, by hydroformylation and        hydrogenation to hydroxy fatty acid esters.    -   Polyhydrocarbonpolyols, also known as oligohydrocarbonols, for        example poly-hydroxy-functional ethylene-propylene,        ethylene-butylene or ethylene-propylene-diene copolymers, as        produced, for example, by Kraton Polymers, or        poly-hydroxy-functional copolymers of dienes such as        1,3-butadiene or diene mixtures, and vinyl monomers such as        styrene, acrylonitrile or isobutylene, or        poly-hydroxy-functional polybutadienepolyols, for example those        which are prepared by copolymerization of 1,3-butadiene and        allyl alcohol and may also be hydrogenated.    -   poly-hydroxy-functional acrylonitrile/butadiene copolymers, as        can be prepared, for example, from epoxides or amino alcohols        and carboxyl-terminated acrylonitrile/butadiene copolymers        (commercially available under the Hycar® CTBN name from Hanse        Chemie).

These polyols mentioned preferably have a mean molecular weight of250-30 000 g/mol, especially of 400-20 000 g/mol, and preferably have amean OH functionality in the range from 1.6 to 3.

In addition to these polyols mentioned, small amounts of low molecularweight di- or polyhydric alcohols, for example 1,2-ethanediol, 1,2- and1,3-propanediol, neopentyl glycol, diethylene glycol, triethyleneglycol, the isomeric dipropylene glycols and tripropylene glycols, theisomeric butanediols, pentanediols, hexanediols, heptanediols,octanediols, nonanediols, decanediols, undecanediols, 1,3- and1,4-cyclohexanedimethanol, hydrogenated bisphenol A, dimeric fattyalcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol,pentaerythritol, sugar alcohols such as xylitol, sorbitol or mannitol,sugars such as sucrose, other higher polyhydric alcohols, low molecularweight alkoxylation products of the aforementioned di- and polyhydricalcohols, and mixtures of the aforementioned alcohols, can be usedadditionally in the preparation of the polyurethane polymer PUP. It islikewise possible to use small amounts of polyols with a mean OHfunctionality of more than 3, for example sugar polyols.

The polyisocyanates used for the preparation of a polyurethane polymerPUP having aromatic isocyanate groups are aromatic polyisocyanates,especially the diisocyanates. Suitable aromatic polyisocyanates are, forexample, 2,4- and 2,6-tolylene diisocyanate and any desired mixtures ofthese isomers (TDI), 4,4′-, 2,4′- and 2,2′-diphenylmethane diisocyanateand any desired mixtures of these isomers (MDI), mixtures of MDI and MDIhomologs (polymeric MDI or PMDI), 1,3- and 1,4-phenylene diisocyanate,2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-d iisocyanatodiphenyl (TODI),dianisidine diisocyanate (DADI), oligomers and polymers of theaforementioned isocyanates, and any desired mixtures of theaforementioned isocyanates. Preference is given to MDI and TDI.

The aromatic polyisocyanates mentioned are commercially available.

In a second embodiment, the polyisocyanate P having aromatic isocyanategroups is an aromatic polyisocyanate PI. The aromatic polyisocyanate PIis especially an aromatic diisocyanate, or a low molecular weightoligomer of an aromatic diisocyanate, or a derivative of an aromaticdiisocyanate, or any desired mixture of these isocyanates. Suitablearomatic polyisocyanates PI are, for example, 2,4- and 2,6-tolylenediisocyanate and any desired mixtures of these isomers (TDI), 4,4′-,2,4′- and 2,2′-diphenylmethane diisocyanate and any desired mixtures ofthese isomers (MDI), mixtures of MDI and MDI homologs (polymeric MDI orPMDI), 1,3- and 1,4-phenylene diisocyanate,2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODI),dianisidine diisocyanate (DADI), oligomers and polymers of theaforementioned isocyanates, and any desired mixtures of theaforementioned isocyanates.

Preferred polyisocyanates PI are room temperature liquid forms of MDI(so-called “modified MDI”), which are mixtures of MDI with MDIderivatives, for example MDI carbodiimides, MDI uretonimines or MDIurethanes, known, for example, under trade names such as Desmodur® CD,Desmodur® PF, Desmodur® PC (all from Bayer), Lupranat® MM 103 (fromBASF), Isonate® M 143 (from Dow), Suprasec® 2020, Suprasec® 2388 (bothfrom Huntsman); technical grade forms of PMDI, for example obtainableunder trade names such as Desmodur® VL, VL 50, VL R 10, VL R 20 andDesmodur® VKS 20 F (all from Bayer), Lupranat® M 10 R, Lupranat® M 20 R(both from BASF), Isonate® M 309, Voranate® M 229, Voranate M® 580 (allfrom Dow), Suprasec® 5025, Suprasec® 2050, Suprasec® 2487 (all fromHuntsman); and technical grade forms of oligomeric TDI, for exampleDesmodur® IL (Bayer). The aforementioned polyisocyanates are typicallymixtures of substances with different degrees of oligomerization and/orchemical structures. They preferably have a mean NCO functionality of2.1 to 4.0 and contain especially isocyanurate, iminooxadiazinedione,uretdione, urethane, biuret, allophanate, carbodiimide, uretonimine oroxadiazinetrione groups.

In a third embodiment, the polyisocyanate P is a mixture consisting ofat least one polyurethane polymer PUP and at least one polyisocyanatePI, as have been described above.

Typically, the polyisocyanate P is present in an amount of 5 to 95% byweight, preferably in an amount of 10 to 90% by weight, based on theoverall composition. In filled compositions, i.e. compositions whichcomprise a filler, the polyisocyanate P is preferably present in anamount of 5 to 60% by weight, especially 10 to 50% by weight, based onthe overall composition.

The composition comprises, in addition to at least one polyisocyanate Phaving aromatic isocyanate groups, at least one dialdimine A of theformula

Preferably, Y¹ and Y² are each a methyl group.

Preferably, Y³ is a radical of the formula (II) or (III)

-   -   where R³ is a hydrogen atom or an alkyl or arylalkyl group,        especially having 1 to 12 carbon atoms, preferably a hydrogen        atom;    -   R⁴ is a hydrocarbon radical having 1 to 30, especially 11 to 30,        carbon atoms, which optionally contains heteroatoms; and    -   R⁵    -   is a hydrogen atom or    -   is a linear or branched alkyl radical having 1 to 30, especially        11 to 30, carbon atoms, optionally with cyclic components and        optionally with at least one heteroatom, or    -   is a mono- or polyunsaturated, linear or branched hydrocarbon        radical having 5 to 30 carbon atoms, or    -   is an optionally substituted aromatic or heteroaromatic 5- or        6-membered ring.

More preferably, Y³ is a radical of the formula (III).

The broken lines in the formulae in this document each represent thebond between a substituent and the corresponding molecular radical.

A dialdimine A of the formula (I) is obtainable by a condensationreaction with elimination of water between at least one diamine DA ofthe formula (IV) and at least one aldehyde ALD of the formula (V). Thealdehyde ALD of the formula (V) is used here stoichiometrically or in astoichiometric excess in relation to the amino groups of the diamine.

In the formulae (IV) and (V), X, Y¹, Y² and Y³ each have the definitionsalready mentioned.

It is essential for the present invention that the two primary aminogroups of the diamine DA differ from one another either in the number ofthe hydrogen atoms on the carbon atoms (C_(α)) in the α position (=1position) to the particular amino groups by at least one, or in thenumber of hydrogen atoms on the carbon atoms (C_(β)) in the β position(=2 position) to the particular amino groups by at least two.

H₂N—C_(α)C_(β)—C_(γ)—C_(δ)—

The diamine DA thus has different substitution patterns on the α carbonatoms and on the β carbon atoms to the particular amino group. Diamineshaving such different substitution are also referred to in the presentdocument as “asymmetric”. This different substitution leads to adifferent reactivity of the two primary amino groups, especially towardisocyanate groups.

The diamine DA thus differs, in one embodiment, in the substitutionpattern on the carbon atoms which are in the a position to the primaryamino groups.

Such diamines DA are, for example, 1,2-propanediamine,2-methyl-1,2-propanediamine, 1,3-butanediamine, 1,3-diaminopentane(DAMP), 4-aminoethylaniline, 4-aminomethylaniline,4-[(4-aminocyclohexyl)methyl]aniline, 2-aminoethylaniline,2-aminomethylaniline, 2-[(4-aminocyclo-hexyl)methyl]aniline and4-[(2-aminocyclohexyl)methyl]aniline.

In another embodiment, the diamine DA thus differs in the substitutionpattern at the carbon atoms which are in the β position to the primaryamino groups.

Such diamines DA are, for example, 2,2,4-trimethylhexamethylenediamine(TMD), 1,5-diamino-2-butyl-2-ethyl-pentane,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(=isophoronediamine=IPDA) and 1,4-diamino-2,2,6-trimethylcyclohexane(TMCDA).

The diamine DA has two primary amino groups, of which at least one isaliphatic. The second amino group may be an aliphatic or aromatic aminogroup.

Diamines DA of the formula (IV) are not considered to include diamineswhose amino groups differ from one another only by one hydrogen atom onthe carbon atoms (C_(β)) in the β position to the particular aminogroups. One example of such a diamine which is not a diamine DA is2-methyl-pentamethylenediamine (=1,5-diamino-2-methylpentane=MPMD).Diamines DA of the formula (IV) are likewise considered not to includediamines whose amino groups differ from one another merely in the numberof the hydrogen atoms on the carbon atoms (C_(γ) and C_(δ)) in the γ orδ position to the particular amino groups. In all these cases, thedifferent substitution pattern on the diamine brings about an onlyinsignificant difference, if any, in the reactivity of the amino groups,especially toward isocyanate groups.

The diamine DA of the formula (IV) is preferably selected from the groupconsisting of 1,3-diaminopentane (DAMP),1,5-diamino-2-butyl-2-ethylpentane, 2,2,4-trimethylhexamethylenediamine(TMD) and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(=isophoronediamine=IPDA).

The aldehyde ALD which can be used to prepare a dialdimine A of theformula (I) has the formula (V) and is a tertiary aliphatic or tertiarycycloaliphatic aldehyde. Suitable aldehydes ALD are, for example,pivalaldehyde (=2,2-dimethylpropanal), 2,2-dimethylbutanal,2,2-diethylbutanal, 1-methylcyclopentanecarboxaldehyde,1-methylcyclohexanecarboxaldehyde; ethers formed from2-hydroxy-2-methylpropanal and alcohols such as propanol, isopropanol,butanol and 2-ethylhexanol; esters formed from2-formyl-2-methylpropionoic acid or 3-formyl-3-methylbutyric acid andalcohols such as propanol, isopropanol, butanol and 2-ethylhexanol;esters formed from 2-hydroxy-2-methylpropanal and carboxylic acids suchas butyric acid, isobutyric acid and 2-ethylhexanoic acid; and theethers and esters, described as particularly suitable hereinafter, of2,2-disubstituted 3-hydroxypropanals, -butanals or analogous higheraldehydes, especially of 2,2-dimethyl-3-hydroxypropanal.

In one embodiment, particularly suitable aldehydes ALD of the formula(V) are aldehydes ALD1 of the formula (VI), i.e. aldehydes ALD of theformula (V) with the Y³ radical of the formula (II).

In formula (VI), Y¹ and Y² are preferably each a methyl group and R³ ispreferably a hydrogen atom.

The aldehydes ALD1 of the formula (VI) are ethers of aliphatic,arylaliphatic or cycloaliphatic 2,2-disubstituted 3-hydroxyaldehydeswith alcohols or phenols of the formula R⁴—OH, for example fattyalcohols or phenol. Suitable 2,2-disubstituted 3-hydroxyaldehydes are inturn obtainable from aldol reactions, especially crossed aldolreactions, between primary or secondary aliphatic aldehydes, especiallyformaldehyde, and secondary aliphatic, secondary arylaliphatic orsecondary cycloaliphatic aldehydes, for example isobutyraldehyde,2-methylbutyraldehyde, 2-ethylbutyraldehyde, 2-methyl-valerald ehyde,2-ethylcapronaldehyde, cyclopentanecarboxaldehyde,cyclo-hexanecarboxaldehyde, 1,2,3,6-tetrahydrobenzaldehyde,2-methyl-3-phenylpropionaldehyde, 2-phenylpropionaldehyde(hydratropaldehyde) or diphenyl-acetaldehyde. Examples of suitable2,2-disubstituted 3-hydroxyaldehydes are 2,2-dimethyl-3-hydroxypropanal,2-hydroxymethyl-2-methylbutanal, 2-hydroxymethyl-2-ethylbutanal,2-hydroxymethyl-2-methylpentanal, 2-hydroxymethyl-2-ethylhexanal,1-hydroxymethylcyclopentanecarboxaldehyde,1-hydroxy-methylcyclohexanecarboxaldehyde1-hydroxymethylcyclohex-3-enecarbox-aldehyde,2-hydroxymethyl-2-methyl-3-phenylpropanal,3-hydroxy-2-methyl-2-phenylpropanal and 3-hydroxy-2,2-diphenylpropanal.

Examples of such aldehydes ALD1 of the formula (VI) which should bementioned are 2,2-dimethyl-3-(2-ethylhexyloxy)propanal,2,2-dimethyl-3-lauroxypropanal, 2,2-dimethyl-3-stearoxypropanal,3-cyclohexyloxy-2,2-dimethylpropanal and 2,2-dimethyl-3-phenoxypropanal.

In a further embodiment, particularly suitable aldehydes ALD of theformula (V) are aldehydes ALD2 of the formula (VII), i.e. aldehydes ALDof the formula (V) with the Y³ radical of the formula (III).

In formula (VII), Y¹ and Y² are preferably each a methyl group, and R³is preferably a hydrogen atom.

The aldehydes ALD2 of the formula (VII) are esters of the2,2-disubstituted 3-hydroxyaldehydes already described with suitablecarboxylic acids.

Examples of suitable carboxylic acids are saturated aliphatic carboxylicacids such as formic acid, acetic acid, propionic acid, butyric acid,isobutyric acid, valeric acid, caproic acid, 2-ethylcaproic acid,enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoicacid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid,palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachicacid; monounsaturated aliphatic carboxylic acids such as palmitoleicacid, oleic acid, erucic acid; polyunsaturated aliphatic carboxylicacids such as linoleic acid, linolenic acid, eleostearic acid,arachidonic acid; cycloaliphatic carboxylic acids such ascyclohexanecarboxylic acid; arylaliphatic carboxylic acids such asphenylacetic acid; aromatic carboxylic acids such as benzoic acid,naphthoic acid, toluic acid, anisic acid; isomers of these acids; fattyacid mixtures from the industrial hydrolysis of natural oils and fats,for example rapeseed oil, sunflower oil, linseed oil, olive oil, coconutoil, oil palm kernel oil and oil palm oil; and monoalkyl and monoaryldicarboxylates as obtained from the monoesterification of dicarboxylicacids such as succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid,maleic acid, fumaric acid, hexahydrophthalic acid, hexahydroisophthalicacid, hexahydroterephthalic acid, 3,6,9-trioxa-undecanoic acid andsimilar derivatives of polyethylene glycol, with alcohols such asmethanol, ethanol, propanol, butanol, higher homologs and isomers ofthese alcohols.

Preferred aldehydes ALD2 of the formula (VII) are3-benzoyloxy-2,2-di-methylpro pa nal,3-cyclohexanoyloxy-2,2-dimethylpropanal, 2,2-dimethyl-3-(2-ethylhexyloxy)propanal, 2,2-dimethyl-3-lauroyloxypropanal,2,2-dimethyl-3-myristoyloxypropanal,2,2-dimethyl-3-palmitoyloxypropanal, 2,2-dimethyl-3-stearoyloxypropanal,and analogous esters of other 2,2-disubstituited 3-hydroxyaldehydes.

In a particularly preferred embodiment, R⁵ is selected from the groupconsisting of phenyl, cyclohexyl, 2-ethylhexyl and the C₁₁—, C₁₃-, C₁₅-and C₁₇-alkyl groups.

The most preferred aldehyde of the formula (VII) is2,2-dimethyl-3-lauroyloxypropanal.

In a preferred preparation method of the aldehyde ALD2 of the formula(VII), a 2,2-disubstituted 3-hydroxyaldehyde, for example2,2-dimethyl-3-hydroxypropanal, which can be prepared, for example, fromformaldehyde (or paraformaldehyde) and isobutyraldehyde, optionally insitu, is reacted with a carboxylic acid to give the corresponding ester.This esterification can be effected by known methods without the use ofsolvents, described, for example, in Houben-Weyl, “Methoden derorganischen Chemie” [Methods of Organic Chemistry], vol. VIII, pages516-528.

The aldehydes ALD2 of the formula (VII) are preferred over the aldehydesALD1 of the formula (VI) owing to their ease of preparability.

In a particularly preferred embodiment, the aldehyde ALD of the formula(V) is odorless. An “odorless” substance is understood to mean asubstance which has such a low odor that most humans cannot smell it,i.e. cannot perceive it with the nose.

Odorless aldehydes ALD of the formula (V) are firstly especiallyaldehydes ALD1 of the formula (VI) in which the R⁴ radical is ahydrocarbon radical which has 11 to 30 carbon atoms and optionallycontains heteroatoms.

Secondly, odorless aldehydes ALD of the formula (V) are especiallyaldehydes ALD2 of the formula (VII) in which the R⁵ radical is either alinear or branched alkyl group having 11 to 30 carbon atoms, optionallywith cyclic components, and optionally having at least one heteroatom,especially having at least one ether oxygen, or a mono- orpolyunsaturated linear or branched hydrocarbon chain having 11 to 30carbon atoms.

Examples of odorless aldehydes ALD2 of the formula (VII) areesterification products of the 2,2-disubstituted 3-hydroxyaldehydesalready mentioned with carboxylic acids, for example lauric acid,tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid,margaric acid, stearic acid, nonadecanoic acid, arachic acid,palmitoleic acid, oleic acid, erucic acid, linoleic acid, linolenicacid, eleostearic acid, arachidonic acid, and fatty acid mixtures fromthe industrial hydrolysis of natural oils and fats, for example rapeseedoil, sunflower oil, linseed oil, olive oil, coconut oil, oil palm kerneloil and oil palm oil.

Preferred odorless aldehydes of the formula (VII) are2,2-dimethyl-3-lauroyloxypropanal, 2,2-dimethyl-3-myristoyloxypropanal,2,2-dimethyl-3-palmitoyloxypropanal and2,2-dimethyl-3-stearoyloxypropanal. Particular preference is given to2,2-dimethyl-3-lauroyloxypropanal.

The dialdimines A of the formula (I) have the property that they do notreact with isocyanates in the absence of water. This means, moreparticularly, that their X, Y¹, Y² and Y³ radicals do not have anymoieties which are reactive with isocyanate groups. More particularly,X, Y¹, Y² and Y³ have no hydroxyl groups, no primary or secondary aminogroups, no mercapto groups and no other groups with active hydrogen.

The dialdimines A of the formula (I) also have the property that theiraldimino groups cannot tautomerize to enamino groups, since they do notcontain any hydrogen as substituents in a position to the carbon atom ofthe aldimino group. Owing to this property, they form, together withpolyisocyanates P having aromatic isocyanate groups, particularlystorable, i.e. substantially viscosity-stable, mixtures.

Dialdimines A which have been prepared proceeding from odorlessaldehydes of the above-described particularly preferred embodiment areodorless. Such odorless dialdimines A are particularly preferred. Formany applications, odorlessness is a great advantage or an indispensableprerequisite, especially in closed spaces such as in the interior ofbuildings or vehicles, and in large-area applications, for example inthe case of application of floor coverings.

The dialdimines A are storage-stable under suitable conditions,especially with exclusion of moisture. On ingress of moisture, theiraldimino groups can be hydrolyzed formally via intermediates to aminogroups, releasing the corresponding aldehyde ALD of the formula (V) usedto prepare the dialdimine A. Since this hydrolysis reaction isreversible and the chemical equilibrium is clearly on the aldimine side,it can be assumed that only some of the aldimino groups are hydrolyzedin the absence of groups reactive toward amines.

In the presence of isocyanate groups, the hydrolysis equilibrium shifts,since the aldimino groups being hydrolyzed react irreversibly with theisocyanate groups to give urea groups. The reaction of the isocyanategroups with the aldimino groups being hydrolyzed need not necessarilyproceed via free amino groups. It will be appreciated that reactionswith intermediates of the hydrolysis reaction are also possible. Forexample, it is conceivable that an aldimino group being hydrolyzedreacts directly in the form of a hemiaminal with an isocyanate group.

The dialdimine A is preferably present in the composition in a slightlysuperstoichiometric, stoichiometric or substoichiometric amount, basedon the isocyanate groups. The dialdimine A of the formula (I) isadvantageously present in the composition in such an amount that theratio between the number of the aldimino groups and the number of theisocyanate groups is 0.1 to 1.1, especially 0.15 to 1.0, more preferably0.2 to 0.9.

The dialdimines A used may also be mixtures of different dialdimines A.More particularly, it is possible to use mixtures of differentdialdimines A which have been prepared proceeding from mixtures ofdifferent diamines DA of the formula (IV) and/or mixtures of differentaldehydes ALD of the formula (V).

It is also possible that, in addition to at least one dialdimine A,further polyaldimines are present in the composition. For example, it ispossible to react a diamine DA of the formula (IV) with a mixturecomprising an aldehyde ALD and a dialdehyde. It is equally possible forthis purpose to use an aldehyde mixture which, as well as an aldehydeALD, comprises further aldehydes.

In addition to at least one polyisocyanate P having aromatic isocyanategroups and at least one dialdimine A of the formula (I), the compositionmay comprise further assistants and additives.

The composition reacts with water or moisture and is crosslinked as aresult. When sufficient water is present to convert a majority of or allisocyanate groups, this gives rise to a cured composition which hasexcellent mechanical properties. The composition can therefore bedescribed as “moisture-curing”.

The composition may be present in the form of a one-componentcomposition or in the form of a two-component composition. One-componentcompositions have the advantage that they are applicable without amixing operation, whereas two-component compositions have the advantagethat they cure more rapidly and may contain, as constituents, substanceswhich are not storable together with isocyanates.

In one embodiment, the composition is present in the form of aone-component composition.

A preferred polyisocyanate P having aromatic isocyanate groups in theone-component composition is a polyurethane polymer PUP as has beendescribed above.

Suitable assistants and additives for the one-component composition are,for example, the following substances:

-   -   plasticizers, for example carboxylic esters such as phthalates,        for example dioctyl phthalate, diisononyl phthalate or        diisodecyl phthalate, adipates, for example dioctyl adipate,        azelates and sebacates, organic phosphoric and sulfonic esters        or polybutenes;    -   solvents;    -   inorganic and organic fillers, for example ground or        precipitated calcium carbonates optionally coated with        stearates, carbon blacks, especially industrially produced        carbon blacks (referred to hereinafter as “carbon black”),        barite (BaSO₄, also known as heavy spar), kaolins, aluminum        oxides, aluminum hydroxides, silicas, especially high-dispersity        silicas from pyrolysis processes, PVC powders or hollow spheres;    -   fibers, for example of polyethylene;    -   pigments, for example titanium dioxide or iron oxides;    -   catalysts which accelerate the hydrolysis of the aldimino        groups, especially acids or compounds which are hydrolyzable to        acids, for example organic carboxylic acids such as benzoic        acid, salicylic acid or 2-nitrobenzoic acid, organic carboxylic        anhydrides such as phthalic anhydride or hexahydrophthalic        anhydride, sayl esters of organic carboxylic acids, organic        sulfonic acids such as methanesulfonic acid, p-toluenesulfonic        acid or 4-dodecylbenzenesulfonic acid, or further organic or        inorganic acids;    -   catalysts which accelerate the reaction of the isocyanate groups        with water, especially metal compounds, for example tin        compounds such as dibutyltin diacetate, dibutyltin dilaurate,        dibutyltin distearate, dibutyltin diacetylacetonate, dioctyltin        dilaurate, dibutyltin dichloride and dibutyltin oxide, tin(II)        carboxylates, stannoxanes such as laurylstannoxane, bismuth        compounds such as bismuth(III) octoate, bismuth(III)        neodecanoate or bismuth(III) oxinates; and tertiary amines, for        example 2,2′-dimorpholinodiethyl ether and other morpholine        ether derivatives;    -   rheology modifiers, for example thickeners or thixotropic        agents, for example urea compounds, polyamide waxes, bentonites        or fumed silicas;    -   reactive diluents and crosslinkers, for example monomeric        polyisocyanates such as MDI, TDI, mixtures of MDI and MDI        homologs (polymeric MDI or PMDI), and oligomers of these        polyisocyanates, especially in the form of iso-cyanurates,        carbodiimides, uretonimines, biurets, allophanates or        iminooxadiazinediones, adducts of monomeric polyisocyanates with        short-chain polyols, and also adipic dihydrazide and other        dihydrazides, and also capped amines in the form of aldimines,        ketimines, oxazolidines or enamines;    -   desiccants, for example molecular sieves, calcium oxide,        high-reactivity isocyanates such as p-tosyl isocyanate,        orthoformic esters, alkoxysilanes such as tetraethoxysilane,        organoalkoxysilanes such as vinyltri-methoxysilane, and        organoalkoxysilanes which have a functional group in the a        position to the silane group;    -   adhesion promoters, especially organoalkoxysilanes, for example        epoxysilanes, vinylsilanes, (meth)acryloylsilanes,        isocyanatosilanes, carbamatosilanes,        S-(alkylcarbonyl)mercaptosilanes and aldiminosilanes, and        oligomeric forms of these silanes;    -   stabilizers against heat, light and UV radiation;    -   flame retardant substances;    -   surface active substances, for example wetting agents, leveling        agents, devolatilizers or defoamers;    -   biocides, for example algicides, fungicides or substances which        inhibit fungal growth.

It is advantageous to ensure that such additives do not impair thestorage stability of the composition. This means that these additivesmust not trigger the reactions which lead to crosslinking, such ashydrolysis of the aldimino groups or crosslinking of the isocyanategroups, to a significant degree during storage. More particularly, thismeans that all of these additives should contain at most traces ofwater, if any. It may therefore be advisable to chemically or physicallydry certain additives before they are mixed into the composition.

The one-component composition described preferably comprises, as well asat least one polyisocyanate P and at least one dialdimine A of theformula (I), at least one catalyst. The catalyst is especially one ofthe acids mentioned, such as benzoic acid or salicylic acid, or one ofthe metal compounds mentioned, or one of the tertiary amines mentioned.In particular, this catalyst is a catalyst which accelerates thehydrolysis of the aldimino groups, preferably an acid. It may quitepossibly also be advantageous when different catalysts or differentcatalyst types are mixed with one another.

The one-component composition is preferably produced and stored withexclusion of moisture. In a suitable package or arrangement, imperviousto ambient conditions, for example a vat, a pouch or a cartridge, itpossesses an excellent storage stability. The terms “storage-stable” and“storage stability” in connection with a composition refers, in thepresent document, to the fact that the viscosity of the composition at agiven application temperature and in the course of suitable storagewithin the period considered rises, if at all, at most to such an extentthat the composition remains usable in the manner intended.

When the one-component composition comes into contact with moisture orwater, the aldimino groups of the dialdimine A begin to undergohydrolysis. The isocyanate groups present in the composition then reactwith the aldimino groups being hydrolyzed to release at least onealdehyde ALD of the formula (V). Excess isocyanate groups in relation tothe aldimino groups react directly with water. As a result of thesereactions, the composition crosslinks and ultimately cures to give asolid material. The reaction of the isocyanate groups with the aldiminogroups being hydrolyzed need not necessarily proceed via free aminogroups; reactions with intermediates of the hydrolysis reaction are alsopossible. For example, it is conceivable that an aldimino group beinghydrolyzed reacts directly with an isocyanate group in the form of ahemiaminal.

The water required for the curing reaction may either originate from theair (air humidity), or else the composition can be contacted with awater-containing component, for example by spraying, or awater-containing component can be added to the composition in the courseof application, especially by mixing it in.

The composition generally cures without bubbles, especially also at ahigh curing rate.

The curing rate can be influenced via the type and amount of one or morecatalysts which may be present, by the temperature which exists in thecourse of curing and by the air humidity or the amount of water added.

When a water-containing component is added to the composition, thecomposition is cured in a greatly accelerated manner compared to curingexclusively with air humidity. In this case, the prolonged open time ofthe compositions described here is a particularly great advantage. Inthis way, compositions which possess very rapid curing coupled with apracticable open time are obtainable.

In a further embodiment, the composition is present in the form of atwo-component composition. A two-component composition consists of acomponent K1 and of a component K2, which are stored separately from oneanother and are mixed with one another only briefly before application.

In one embodiment of a two-component composition, the polyisocyanate Phaving aromatic isocyanate groups and the dialdimine A of the formula(I) are part of the first component K1, and the second component K2comprises compounds reactive toward isocyanate groups, especially waterand/or polyols and/or polyamines.

In another embodiment of a two-component composition, the polyisocyanateP having aromatic isocyanate groups is part of the first component K1,whereas the second component K2 comprises the dialdimine A of theformula (I) and compounds reactive toward isocyanate groups, especiallywater and/or polyols and/or polyamines.

Component K2 preferably comprises at least one dialdimine A of theformula (I) and water.

Component K2 preferably comprises at least one dialdimine A of theformula (I) and at least one polyol, in which case preferably 0.3 to 1equivalent of aldimino groups per equivalent of hydroxyl groups ispresent in the composition.

More preferably, component K2 comprises at least one dialdimine A of theformula (I), at least one polyol and water, in which case preferably 0.3to 1 equivalent of aldimino groups per equivalent of hydroxyl groups ofthe polyol is present in the composition, and the water is preferablypresent in a substoichiometric amount based on the aldimino groups.

In both above-described embodiments of the two-component compositions,suitable polyols are the same commercial polyols as have already beenmentioned above as suitable for preparing a polyurethane polymer PUP,and those low molecular weight di- or polyhydric alcohols as have beenmentioned above as suitable for additional use in the preparation of apolyurethane polymer PUP. If the component K2 comprises water, it isadvantageous when the amount of water is at most that required tohydrolyze the dialdimine A—and if appropriate any further latenthardeners. In addition, both components may comprise further assistantsand additives as have already been mentioned above for a one-componentcomposition. In the case of component K2, however, further assistantsand additives are additionally also possible. More particularly, theseare those assistants and additives which are storable only for a shortperiod, if at all, with aromatic isocyanate groups. In particular, theseare catalysts such as:

compounds of zinc, manganese, iron, chromium, cobalt, copper, nickel,molybdenum, lead, cadmium, mercury, antimony, vanadium, titanium,zirconium or potassium, such as zinc(II) acetate, zinc(II)2-ethylhexanoate, zinc(11) laurate, zinc(II) oleate, zinc(II)naphthenate, zinc(II) acetylacetonate, zinc(II) salicylate,manganese(II) 2-ethylhexanoate, iron(III) 2-ethylhexanoate, iron(III)acetylacetonate, chromium(III) 2-ethylhexanoate, cobalt(II) naphthenate,cobalt(II) 2-ethylhexanoate, copper(II) 2-ethylhexanoate, nickel(II)naphthenate, phenylmercuric neodecanoate, lead(II) acetate, lead(II)2-ethylhexanoate, lead(II) neodecanoate, lead(II) acetylacetonate,aluminum lactate, aluminum oleate, aluminum(III) acetylacetonate,diisopropoxytitanium bis(ethylacetoacetate), dibutoxytitaniumbis(ethylacetoacetate), dibutoxytitanium bis(acetylacetonate), potassiumacetate, potassium octanoate; tertiary amine compounds, such astriethylamine, tributylamine, N-ethyldiisopropylamine,N,N,N′,N′-tetramethylethylenediamine, pentamethyldi-ethylenetriamine andhigher homologs thereof, N,N,N′,N′-tetramethylpropylenediamine,pentamethyldipropylenetriamine and higher homologs thereof,N,N,N′,N′-tetramethyl-1,3-butanediamine,N,N,N′N′-tetramethyl-1,6-hexanediamine, bis(dimethylamino)methane,N,N-dimethyl-benzylamine, N,N-dimethylcyclohexylamine,N-methyldicyclohexylamine, N,N-dimethylhexadecylamine,bis(N,N-diethylaminoethyl) adipate, N,N-dimethyl-2-phenylethylamine,tris(3-dimethylaminopropyl)amine, 1,4-diazabicyclo[2.2.2]octane (DABCO),1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), diazabicyclo[4.3.0]nonene(DBN) N-methylmorpholine, N-ethylmorpholine, N-cocomorpholine,N,N′-dimethylpiperazine, N-methyl-N′-dimethylaminoethylpiperazine,bis(dimethylaminoethyl)piperazine,1,3,5-tris(dimethylaminopropyl)hexahydrotriazine orbis(2-dimethylaminoethyl) ether; aromatic nitrogen compounds, such as4-dimethylaminopyridine, N-methylimidazole, N-vinylimidazole or1,2-dimethylimidazole; amidines and guanidines, such as1,1,3,3-tetramethylguanidine; tertiary amine compounds containing activehydrogen atoms, such as triethanolamine, triisopropanolamine,N-methyldiethanolamine, N,N-dimethylethanolamine,3-(dimethylamino)propyldiisopropanolamine,bis(3-(dimethylamino)propyl)iso-propanolamine,bis(3-dimethylaminopropyl)amine, 3-(dimethyl-amino)propylurea, Mannichbases, such as 2,4,6-tris(dimethyl-aminomethyl)phenol or2,4,6-tris(3-(dimethylamino)propylaminomethyl)phenol,N-hydroxypropylimidazole, N-(3-aminopropyl)imidazole, and alkoxylationand polyalkoxylation products of these compounds, for exampledimethylaminoethoxyethanol; organic ammonium compounds, such asbenzyltrimethylammonium hydroxide, or alkoxylated tertiary amines;so-called “delayed action” catalysts, which are modifications of knownmetal or amine catalysts, such as reaction products of tertiary aminesand carboxylic acids or phenols, for example of1,4-diazabicyclo[2.2.2]octane or DBU and formic acid or acetic acid; andcombinations of the compounds mentioned, especially of metal compoundsand tertiary amines.

Component K2 preferably does not contain any isocyanate groups.

If the composition comprises further capped amines, especiallyaldimines, ketimines, oxazolidines or enamines, they may be part ofcomponent K1 and/or K2. Suitable aldimines are especially aldimineswhich are different than the dialdimines A and are obtainable proceedingfrom amines other than those of the formula (IV) and/or proceeding fromaldehydes other than those of the formula (V). All these capped amineshave the property of releasing amino groups when they are hydrolyzed,which react rapidly with isocyanate groups present.

The two components K1 and K2 are prepared separately from one another,with exclusion of moisture at least for component K1 The two componentsK1 and K2 are storage-stable separately from one another, i.e. they canbe stored in a suitable package or arrangement, for example in a vat, ahobbock, a pouch, a bucket or a cartridge, over several months up to oneyear and longer before they are used, without their particularproperties changing to a degree relevant for the use thereof.

The mixing ratio between the two components K1 and K2 is preferablyselected such that the groups reactive toward isocyanate groups incomponents K1 and K2 are in a suitable ratio relative to the isocyanategroups of component K1. In the two-component composition, before thecuring, suitably 0.1 to 1.1 equivalents, preferably 0.5 to 0.95equivalent and more preferably 0.6 to 0.95 equivalent of the sum of thegroups reactive toward isocyanates is present per equivalent ofisocyanate groups, the aldimino groups and any further capped aminogroups present being counted among the groups reactive towardisocyanates, and water not being counted among the groups reactivetoward isocyanates. Excess isocyanate groups react especially directlywith water, for example with air humidity.

Before or during the application of the two-component composition, thetwo components are mixed with one another by means of a suitableprocess.

The mixing can be effected continuously or batchwise. The mixedcomposition is applied during the mixing or after the mixing, bycontacting it with a solid surface, optionally by means of a suitableassistant. In doing this, it has to be ensured that not too much timelapses between the mixing of components K1 and K2 and the application,since this can result in problems, for example slowed or incompletebuildup of adhesion to the solid surface. The maximum period withinwhich the mixed composition should be applied is referred to as the “potlife” or else as the “open time”. Often, the open time is defined as thetime within which the viscosity of the mixed composition doubles.

After the mixing of components K1 and K2, the curing commences. Thedialdimine A of the formula (I) begins to hydrolyze in the manneralready described and to react with the isocyanate groups as soon as itcomes into contact with water. The water is either already present inthe mixed composition—by virtue of it having been a constituent ofcomponent K2, or by virtue of it having been added to the compositionbefore or during the mixing of the two components K1 and K2—or the waterdiffuses into the mixed composition in the form of air humidity. In thelatter case, the dialdimine A reacts with the isocyanate groups from theoutside inward, in parallel to the penetration of the air humidity intothe composition. As already described, the reaction of the isocyanategroups with the aldimino groups being hydrolyzed need not necessarilyproceed via free amino groups, but can also proceed via intermediates ofthe hydrolysis reaction. In the same way, the reactive groups arereleased from further latent hardeners which may be present in thecomposition. In addition, after the mixing of components K1 and K2, anycompounds which are reactive toward isocyanate groups and are present inthe composition, such as especially polyols and polyamines, react withthe isocyanate groups. Excess isocyanate groups react especiallydirectly with water. As a result of these reactions, the mixedcomposition crosslinks and ultimately cures to a solid material.

The curing generally proceeds without bubbles, especially at a highcuring rate.

The curing rate can be influenced via the type and amount of one or morecatalysts which may be present, via the temperature which prevails inthe course of curing, and via the air humidity or the amount of waterintroduced via component K2.

Both in the one-component embodiment and in the two-componentembodiment, the composition described possesses firstly a long open timeand secondly a high curing rate. The combination of long open time andrapid curing is extremely desirable for many one-component andtwo-component applications.

For instance, the application of a one-component composition is oftensimpler when, after the application thereof, some time still remains inorder to bring the composition into the desired form before a skin ofpartly cured material has formed on the surface. For example, a jointsealant should still be smoothable for a sufficiently long time afterthe application; an adhesive should still be displaceable withoutresidue, in order to align the joint parts exactly; a coating or acovering should still be levelable or have, for example, rubber pellets,sand or colored chips scattered therein. Subsequently, the compositionshould, however, cure rapidly, in order that it can be subjected to loadas soon as possible and/or in order that it can no longer be soiled bydust.

The application of a two-component composition is also oftensignificantly simpler when it has a prolonged open time, given that boththe mixing operation and the application of the composition, and anysubsequent processing steps needed, for example in order to bring thecomposition into the form desired, proceed within the open time. Atwo-component floor covering, for example, which is mixed batchwise andthen poured onto the substrate and leveled should have a long open timein order that the application can be performed exactly without timepressure. Subsequently, the composition should, though, cure rapidly inorder to be subjectable to load as soon as possible. In the case of afloor covering, it is often an indispensable prerequisite that thecovering has cured no later than the day after the application to suchan extent that it can be walked upon, such that further operations canbe performed.

In the case of a one-component composition, the measure used for theopen time is typically the skin formation time. The “skin formationtime” is understood to mean the period of time between the applicationof the composition and the formation of a skin of partly cured materialon the surface of the applied composition. A measure determined for thecuring rate of a one-component composition which cures from the outsideinward is typically the so-called through-curing. In this case, forexample, the thickness of the cured layer which has formed under definedconditions after a given period of time in the composition applied ismeasured; or the time which is needed to completely harden thecomposition applied in a given layer thickness under defined conditionsis measured.

In the case of a two-component composition, a measure determined for theopen time may be the period of time within which, after the mixing ofthe two components, for example, a particular viscosity rise (forexample a doubling) has occurred, or the composition has a tack-freesurface. A measure which can be determined for the curing rate of atwo-component composition may, for example, be the rise in hardness, forexample the Shore hardness, over the course of time.

By virtue of the inventive compositions, it is now possible to achieveprolonged open time and high curing rates combined with one another inone composition.

The effect of the prolonged open time coupled with high curing rate isclearly identifiable, as the examples which follow show. The reasons forthis have not been studied in detail to date. However, it can be assumedthat the effect can be attributed to the described asymmetry of thedialdimines A of the formula (I), or of the diamines DA of the formula(IV) derived therefrom. On ingress of water, at first almost exclusivelythe more reactive aldimino groups of the dialdimine A or the morereactive amino groups of the diamine DA react with the isocyanate groupsof the polyisocyanate P. However, this does not lead to crosslinking ofthe composition but merely to a slight increase in viscosity, whichbarely limits the open time. Only when the more reactive aldimino groupsor amino groups have been substantially consumed do the slower aldiminogroups or amino groups also begin to react with further isocyanategroups, which now leads directly to the crosslinking of the compositionand advances the curing significantly.

As described, the dialdimines A of the formula (I) are based on specificasymmetric diamines DA of the formula (IV) and tertiary aldehydes ALD ofthe formula (V). The different reactivity of the two amino groups in onediamine DA, the reason for which is the different substitution, istransferred directly to a dialdimine of this diamine DA, in which thetwo aldimino groups likewise have a different reactivity. In theparticular case of a dialdimine A, the difference in reactivity in thealdimino groups, caused by the tertiary—and hence stericallydemanding—structure of the parent aldehyde ALD of the aldimino group, isprobably even enhanced further, by virtue of the sterically demandingaldehyde radical, additionally limiting the accessibility of thealdimino groups—especially when they are present in semihydrolyzed formas hemiaminal groups—and hence lowering the reactivity of the sloweraldimino group to a greater than a proportional degree compared to thatof the faster aldimino group.

The use of the preferred odorless dialdimines A makes it possible toobtain, in particular, also compositions which are odorless before,during and after curing. This property constitutes a great advantageover the prior art and extends the possible uses of these compositionssignificantly.

The compositions described are particularly suitable as one- andtwo-component adhesives, sealants, potting compositions or coatings,especially floor coatings. They are especially suitable as elasticadhesives, elastic sealants, elastic potting compositions or elasticcoatings. They more preferably find use as elastic sealants, since theuse of the specific dialdimines A in the cured state gives rise toparticularly flexible properties.

More particularly, the composition described is suitable as a flexiblesealant for sealing joints of all kinds, especially movement joints inbuilt structures. So-called movement joints are joints which are presentat suitable sites and in suitable widths in built structures in order tobridge movements between components made of rigid construction materialssuch as concrete, stone, plastic and metal. Such movements arise firstlythrough shocks and secondly through temperature changes. The rigidmaterials contract under cold conditions, which makes the joints wider,and they expand under hot conditions, which makes the joints narrower. Asealant which is intended to seal such joints in a lasting manner musthave flexible properties in order to transmit a minimum amount of forceto the substrate when it is expanded and when it is compressed in thejoint, and thus subjected to a minimum amount of stress. Flexibleproperties are understood here to mean a high extensibility coupled witha low extension stress value and a good resilience. The term “extensionstress” refers to the stress which acts in a material in the extendedstate.

Particularly low extension stress values in the cured state arepossessed by sealant compositions which comprise at least one dialdimineA in which X in the formula (I) is the radical of a diamine DA selectedfrom a group consisting of TMD, IPDA and1,5-diamino-2-butyl-2-ethylpentane.

In a further aspect, the invention relates to a process for adhesivebonding a substrate S1 to a substrate S2. This process comprises thesteps of:

-   -   i) applying an above-described composition to a substrate S1;    -   ii) contacting the composition applied with a substrate S2        within the open time of the composition;

or

-   -   i′) applying an above-described composition to a substrate S1        and to a substrate S2;    -   ii′) contacting the compositions applied with one another within        the open time of the composition;    -   said substrate S2 consisting of the same material as, or a        different material than, the substrate S1.

The invention additionally relates to a process for sealing, whichcomprises the step of:

-   -   i″) applying an above-described composition between a substrate        S1 and a substrate S2, such that the composition is in contact        with the substrate S1 and the substrate S2;    -   said substrate S2 consisting of the same material as, or a        different material than, the substrate S1.

The intermediate space between substrate S1 and S2 in the process forsealing is referred to by the person skilled in the art as a joint.Typically, the composition is injected here from cartridges into theprepared joints and then smoothed by hand, by moving a tool usuallywetted with soapy water, for example a spatula, or the user's fingerwetted by soapy water, over the applied sealant such that it has asmooth and even, very slightly inwardly curved surface. Since the useroften only smooths the sealant applied when he or she has applied arelatively large joint area, a relatively long time, for example up toone hour, may pass between the application and the smoothing of thesealant. In order to ensure clean smoothing, it is, however,indispensable that no skin has formed yet on the sealant surface withinthis time. Sealants with a short open time are therefore undesirable forsealant users. In spite of this, it is important that the sealant curesrapidly after the long open time and forms a tack-free surface, sincethe risk of soiling by, for example, dust and sand is great in the caseof a tacky, uncured sealant surface. On the other hand, a sealantcomposition in the cured state should have a minimum level of flexibleproperties. These requirements can be met exceptionally well by thecomposition described.

The invention finally relates to a process for coating a substrate S1which comprises the step of:

-   -   i′″) applying a composition as described herein to a substrate        S1 within the open time of the composition.

In all these processes, the substrates S1 and/or S2 may be a multitudeof materials. More particularly, they are an inorganic substrate such asglass, glass ceramic, concrete, mortar, brick, tile, gypsum, or naturalstone such as granite or marble; a metal or an alloy, such as aluminum,steel, nonferrous metal, galvanized metal; an organic substrate such aswood, a plastic such as PVC, polycarbonate, PMMA, polyethylene,polypropylene, polyester, epoxy resin, polyurethane (PU); a coatedsubstrate such as powder-coated metal or alloy; or a paint or a coating,especially an automotive topcoat.

In all these processes, the substrate S1 and/or the substrate S2 mayhave been pretreated before the adhesive bonding or sealing or coating,especially with a primer or an adhesion promoter composition. Suchpretreatments comprise especially physical and/or chemical cleaning andactivation processes, for example grinding, sandblasting, brushing,corona treatment, plasma treatment, flaming, etching or the like, ortreatment with detergents or solvents, or the application of an adhesionpromoter, of an adhesion promoter solution or of a primer.

These described processes for adhesive bonding, sealing or coating giverise to an article.

This article is especially a built structure, especially a builtstructure in construction or civil engineering, or an industrial good ora consumer good, especially a window, a domestic appliance, or a mode oftransport, especially a water or land vehicle, preferably an automobile,a bus, a truck, a train or a ship, or an installable component of a modeof transport.

EXAMPLES Description of the Test Methods

Infrared spectra were measured on an FT-IR 1600 instrument fromPerkin-Elmer (horizontal ATR analysis unit with ZnSe crystal); thesubstances were applied undiluted as a film. The absorption bands arereported in wavenumbers (cm⁻¹) (measurement window: 4000-650 cm¹).

¹H NMR spectra were measured on a Bruker DPX-300 spectrometer at 300.13MHz. The chemical shifts δ are reported in ppm relative totetramethylsilane (TMS), coupling constants J are reported in Hz. Truecoupling patterns and pseudo coupling patterns were not distinguished.

The viscosity was measured on a thermostated Physica UM cone-plateviscometer (cone diameter 20 mm, cone angle 1°, cone tip-plate distance0.05 mm, shear rate 10 to 1000 s⁻¹).

The amine content of the dialdimines prepared, i.e. the content ofcapped amino groups in the form of aldimino groups, was determinedtitrimetrically (with 0.1N HClO₄ in glacial acetic acid, using crystalviolet), and is always reported in mmol N/g.

a) Preparation of Dialdimines

Dialdimine A-1

A round-bottom flask was initially charged under a nitrogen atmospherewith 55.0 g (0.19 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 15.6 g (0.18 mol of N) of1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (=isophoronediamine,IPDA; Vestamin® IPD, Degussa; amine content 11.68 mmol N/g) were addedslowly from a dropping funnel, in the course of which the mixture heatedup and became increasingly cloudy. Thereafter, the volatile constituentswere removed under reduced pressure (10 mbar, 80° C.).

Yield: 67.1 g of a clear colorless oil with an amine content of 2.73mmol N/g and a viscosity of 190 mP·s at 20° C.

IR: 2952, 2922, 2852, 2819sh, 1738 (C═O), 1666 (C═N), 1464, 1418, 1394,1378, 1364, 1350, 1298, 1248, 1236sh, 1158, 1112, 1048, 1020, 1000, 938,928, 910, 894, 868, 772, 722.

¹H NMR (CDCl₃, 300 K): δ 7.59 and 7.57 (2×s, total 1 H, CH═N([isomers]), 7.47 (s, 1 H, CH═N), 4.03 and 4.01 (2×s, 2×2 H,C(CH₃)₂—CH₂—O), 3.37 (m, 1 H, N—CH^(Cy)), 3.08 (dd, 2 H, J≈11.1,N—CH₂—C^(Cy)), 2.30 (t, 4 H, J 7.5, OC(O)—CH₂—CH₂), 1.61 (m, 4 H,OC(O)—CH₂—CH₂), 1.60-0.85 (m, 65 H, remaining CH).

Dialdimine A-2

A round-bottom flask was initially charged under a nitrogen atmospherewith 55.0 g (0.19 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 9.4 g (0.18 mol of N) of 1,3-diaminopentane(DAMP; Dytek® EP Diamine, Invista; amine content 19.42 mmol N/g) wereadded slowly from a dropping funnel, in the course of which the mixtureheated up and became increasingly cloudy. Thereafter, the volatileconstituents were removed under reduced pressure (10 mbar, 80° C.).Yield: 60.9 g of a clear, pale yellow oil with an amine content of 3.01mmol N/g and a viscosity of 50 mPa·s at 20° C.

IR: 2955sh, 2922, 2868sh, 2852, 1737 (C═O), 1666 (C═N), 1466, 1419,1394, 1373, 1346, 1300, 1248, 1233, 1159, 1112, 1057, 1019, 1000, 935,884, 769br, 722.

Dialdimine A-3

A round-bottom flask was initially charged under a nitrogen atmospherewith 50.0 g (0.18 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 15.8 g (0.17 mol of N) of1,5-diamino-2-butyl-2-ethylpentane (amine content 10.52 mmol N/g) wereadded slowly from a dropping funnel, in the course of which the mixtureheated up and became increasingly cloudy. Thereafter, the volatileconstituents were removed under reduced pressure (10 mbar, 80° C.).Yield: 62.6 g of a clear, almost colorless oil with an amine content of2.64 mmol N/g and a viscosity of 100 mPa·s at 20° C.

IR: 2951, 2922, 2871sh, 2852, 2831sh, 1738(C═O), 1669(C═N), 1463, 1418,1393, 1375, 1341, 1302, 1248, 1234, 1159, 1112, 1019, 999, 935, 874sh,848sh, 777, 722.

Dialdimine A-4

A round-bottom flask was initially charged under a nitrogen atmospherewith 79.4 g (0.28 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 20.0 g (0.25 mol of N) of2,2(4),4-trimethylhexamethylenediamine (Vestamin® TMD, Degussa; aminecontent 12.64 mmol N/g) were added slowly from a dropping funnel, in thecourse of which the mixture heated up and became increasingly cloudy.Thereafter, the volatile constituents were removed under reducedpressure (10 mbar, 80° C.). Yield: 94.4 g of a clear, pale yellow oilwith an amine content of 2.66 mmol N/g and a viscosity of 63 mPa·s at20° C.

IR: 2954, 2920, 2852, 2822sh, 1737 (C═O), 1668 (C═N), 1466, 1418,1392sh, 1374, 1365, 1348, 1301sh, 1248, 1234, 1158, 1112, 1020, 999,932, 867, 722.

Dialdimine A-5

A round-bottom flask was initially charged under a nitrogen atmospherewith 24.3 g (85 mmol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 5.0 g (81 mmol of N) of 4-aminomethylaniline(=4-aminobenzylamine; amine content 16.24 mmol N/g) were added slowlyfrom a dropping funnel, in the course of which the mixture heated up andbecame slightly cloudy. Thereafter, the volatile constituents wereremoved under reduced pressure (10 mbar, 80° C.). Yield: 27.6 g of aclear, pale yellow oil with an amine content of 2.93 mmol N/g and aviscosity of 125 mPa·s at 20° C.

Dialdimine A-6 (Comparative)

A round-bottom flask was initially charged under a nitrogen atmospherewith 60.0 g (0.21 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 11.8 g (0.20 mol of N) of1,5-diamino-2-methylpentane (MPMD; Dytek®A, Invista; amine content 17.04mmol N/g) were added slowly from a dropping funnel, in the course ofwhich the mixture heated up and became increasingly cloudy. Thereafter,the volatile constituents were removed under reduced pressure (10 mbar,80° C.). Yield: 68.2 g of a clear, pale yellow oil with an amine contentof 2.94 mmol N/g and a viscosity of 53 mPa·s at 20° C.

Dialdimine A-7 (Comparative)

A round-bottom flask was initially charged under a nitrogen atmospherewith 80.9 g (0.27 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 25.2 g (0.26 mol of N) of3(4),8(9)-bis-(aminomethyl)tricyclo[5.2.1.0^(2,6)]-decane (TCD-diamine,Celanese; amine content 10.23 mmol N/g) were added slowly from adropping funnel, in the course of which the mixture heated up and becameincreasingly cloudy. Thereafter, the volatile constituents were removedunder reduced pressure (10 mbar, 80° C.). Yield: 100.8 g of a clear,almost colorless oil with an amine content of 2.56 mmol N/g.

Dialdimine A-8 (Comparative)

A round-bottom flask was initially charged under a nitrogen atmospherewith 74.3 g (0.26 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 30.0 g (0.25 mol of N) of polyetherdiamine(polyoxypropylenediamine with a mean molecular weight of approx. 240g/mol; Jeffamine® D-230, Huntsman; amine content 8.29 mmol N/g) wereadded slowly from a dropping funnel, in the course of which the mixtureheated up and became increasingly cloudy. Thereafter, the volatileconstituents were removed under reduced pressure (10 mbar, 80° C.).Yield: 99.5 g of a clear, pale yellow oil with an amine content of 2.50mmol N/g.

Dialdimine A-9 (Comparative)

A round-bottom flask was initially charged under a nitrogen atmospherewith 50.9 g (0.18 mol) of distilled 2,2-dimethyl-3-lauroyloxypropanal.With vigorous stirring, 10.0 g (0.17 mol of N) of1,6-hexamethylenediamine (BASF; amine content 17.04 mmol N/g) were addedslowly from a heated dropping funnel, in the course of which the mixtureheated up and became increasingly cloudy. Thereafter, the volatileconstituents were removed under reduced pressure (10 mbar, 80° C.).Yield: 57.7 g of a clear, pale yellow oil with an amine content of 2.94mmol N/g.

b) Production of Compositions Examples to 5 and Comparative Examples 6to 8

For each example, the particular constituents according to table 1 wereweighed in the parts by weight specified without preceding drying into ascrew top polypropylene cup and mixed by means of a centrifugal mixer(SpeedMixer™ DAC 150, FlackTek Inc.; 1 min at 2500 rpm); the mixture wastransferred immediately into an internally coated aluminum tube whichwas sealed airtight.

The polyurethane polymer PUP-1 was prepared as follows:

1300 g of polyoxypropylenediol (Acclaim® 4200 N, Bayer; OH number 28.5mg KOH/g), 2600 g of polyoxypropylenepolyoxyethylenetriol (Caradol®MD34-02, Shell; OH number 35.0 mg KOH/g), 600 g of4,4′-methylenediphenyl diisocyanate (MDI; Desmodur® 44 MC L, Bayer) and500 g of diisodecyl phthalate (DIDP; Palatinol® Z, BASF) were convertedat 80° C. to an NCO-terminated polyurethane polymer with a content offree isocyanate groups of 2.05% by weight and a viscosity of 31.6 Pa·sat 20° C.

The ratio between the isocyanate groups and the aldimino groups for allexamples is 1.0/0.70.

TABLE 1 Composition of examples 1 to 5 and of comparative examples 6 to8. Example 6 7 8 1 2 3 4 5 (comp.) (comp.) (comp.) PU polymer PUP-1 50.050.0 50.0 50.0 50.0 50.0 50.0 50.0 Dialdimine A-1, A-2, A-3, A-4, A-5,A-6, A-7, A-8, 6.26 5.67 6.47 6.42 5.82 5.81 6.67 6.84 Acid catalyst^(a)0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 ^(a)Salicylic acid (5% by weight indioctyl adipate).

The compositions thus obtained were tested for storage stability, opentime and curing rate.

The storage stability was determined via the change in viscosity duringstorage under hot conditions. To this end, the composition was stored at60° C. in the closed tube in an oven, and the viscosity was measured at20° C. for a first time after 12 hours and for a second time after 7days of storage time. The storage stability is calculated from thepercentage increase in the second viscosity value from the first.

A measure employed for the open time was the skin formation time(“tack-free time”). To measure the skin formation time, a small portionof the composition at room temperature, which had been stored at 40° C.over 2 hours, was applied in a layer thickness of approx. 2 mm tocardboard, and the time taken until, when the surface of the compositionis tapped lightly by means of an LDPE pipette, no residues remained onthe pipette for the first time was determined at 23° C. and 50% relativeair humidity.

A measure employed for the curing rate was the time until thecomposition had cured through. The time until through-curing wasdetermined by pouring the composition as a film in a layer thickness of5 mm into a PTFE mold, which was stored under standard climaticconditions, and, by periodically raising the film edge, the time takenuntil the film was removable without residue for the first time wasdetermined in days.

The results of the tests are listed in table 2.

TABLE 2 Properties of examples 1 to 5 and comparative examples 6 to 8.Example 6 7 8 1 2 3 4 5 (comp.) (comp.) (comp.) Viscosity after 12 h^(a)22.8 27.1 21.7 19.7 23.8 22.4 23.1 20.5 Viscosity after 7 d^(a) 27.030.6 25.0 23.2 26.4 26.2 27.7 25.2 Viscosity increase^(b) 18% 13% 15%18% 11% 17% 20% 23% Skin formation time (min) 70 150 90 65 60 40 45 45Through-curing (d) 2.5 3 3 3 2.5 2.5 2.5 2.5 ^(a)in Pa · s, storage at60° C. ^(b)= (viscosity after 7 d/viscosity after 12 h − 1) × 100%.

Examples 9 and 10 and Comparative Example 11

For each example, the particular constituents according to table 3 wereweighed in the parts by weight specified without preceding drying into ascrew top polypropylene cup, and mixed by means of a centrifugal mixer(SpeedMixer™ DAC 150, FlackTek Inc.; 1 min. at 2500 rpm); the mixturewas transferred immediately into an internally coated aluminum tubewhich was sealed airtight.

The polyurethane polymer PUP-2 was prepared as follows:

180 g of polyoxypropylenediol (Acclaim® 4200 N, Bayer; OH number 28.5 mgKOH/g), 50 g of polyoxypropylenetriol (Acclaim® 6300, Bayer; OH number28.0 mg KOH/g) and 21 g of tolylene diisocyanate (TDI; Desmodur® T 80 P,Bayer) were converted at 80° C. to an NCO-terminated polyurethanepolymer with a content of free isocyanate groups of 1.89% by weight anda viscosity of 13.8 Pa·s at 20° C.

The ratio between the isocyanate groups and the aldimino groups for allexamples is 1.0/0.70.

TABLE 3 Composition of examples 9 and 10 and of comparative example 11Example 11 9 10 (comparative) Polyurethane polymer 50.0 50.0 50.0 PUP-2Dialdimine A-1, A-2, A-8, 5.77 5.23 6.31 Acid catalyst^(a) 0.1 0.1 0.1^(a)Salicylic acid (5% by weight in dioctyl adipate).

The compositions thus obtained were tested for storage stability, opentime (skin formation time) and curing rate (through-curing), asdescribed in example 1.

The results of the tests are listed in table 4.

TABLE 4 Properties of examples 9 and 10 and of comparative example 11.Example 11 9 10 (comparative) Viscosity after 12 h 12.8 13.0 12.0 (Pa ·s)^(a) Viscosity after 7 d (Pa · s)^(a) 15.6 15.6 14.0 Viscosityincrease^(b) 22% 20% 17% Skin formation time (min) 130 295 70Through-curing (d) 4 3.5 3 ^(a)storage at 60° C. ^(b)(viscosity after 7d/viscosity after 12 h − 1) × 100%.

Examples 12 to 15 and comparative examples 16 to 18 One-ComponentElastic Adhesives

For each example, the particular constituents according to table 5 wereprocessed in the parts by weight specified without preceding drying in avacuum mixer with exclusion of moisture to give a homogeneous paste,which was immediately transferred into an internally coated aluminumcartridge and the cartridge was sealed airtight.

The polyurethane polymer PUP-3 was prepared as follows:

3560 g of polyoxypropylenediol (Acclaim® 4200 N, Bayer; OH number 28.1mg KOH/g), 1000 g of polyoxypropylenetriol (Acclaim® 6300, Bayer; OHnumber 28.0 mg KOH/g) and 440 g of tolylene diisocyanate (TDI;Desmodur®T 80 P, Bayer) were converted at 80° C. to an NCO-terminatedpolyurethane polymer with a content of free isocyanate groups determinedby titrimetric means of 2.19% by weight and a viscosity at 20° C. of 10Pa·s.

The thickener was prepared as follows:

A vacuum mixer was initially charged with 3000 g of dilsodecyl phthalate(DIDP; Palatinol® Z, BASF) and 480 g of 4,4′-methylenediphenyldiisocyanate (MDI; Desmodur® 44 MC L, Bayer) and heated gently. Then,with vigorous stirring, 270 g of monobutylamine were slowly addeddropwise. The paste which formed was stirred under reduced pressure withcooling for a further hour.

The ratio between the isocyanate groups and the aldimino groups for allexamples is 1.0/0.67.

TABLE 5 Composition of the one-component elastic adhesives of examples12 to 15 and of comparative examples 16 to 18. Example 16 17 18 12 13 1415 (comp.) (comp.) (comp.) PU polymer 24.0 24.0 24.0 24.0 24.0 24.0 24.0PUP-3 Dialdimine A-1, A-2, A-3, A-4, A-6, A-7, A-8, 3.07 2.78 3.18 3.152.85 3.27 3.36 Plasticizer^(a) 1.93 2.22 1.82 1.85 3.15 1.73 1.64 Chalk38.0 38.0 38.0 38.0 38.0 38.0 38.0 Thickener 28.0 28.0 28.0 28.0 28.028.0 28.0 Titanium 4.5 4.5 4.5 4.5 4.5 4.5 4.5 dioxide Epoxysilane^(b)0.2 0.2 0.2 0.2 0.2 0.2 0.2 Acid catalyst^(c) 0.3 0.3 0.3 0.3 0.3 0.30.3 ^(a)Diisodecyl phthalate (DIDP; Palatinol ® Z, BASF).^(b)3-glycidoxypropyltriethoxysilane (Dynasylan ® GLYEO, Degussa).^(c)Salicylic acid (5% by weight in dioctyl adipate).

The one-component elastic adhesives thus obtained were tested forapplication properties, open time, curing rate and mechanical propertiesafter curing.

Measures employed for the application properties were the sagging andthe threading. To determine the sagging, the adhesive was applied bymeans of a cartridge pistol through a triangular nozzle as a horizontaltriangular bead with a base diameter of 8 mm and a height (distance ofthe triangular tip from the base) of 20 mm onto a vertical piece ofcardboard. After 5 minutes, the extent to which the tip had lowered,i.e. had moved away from the original position in the middle of thetriangular bead, was measured. It was assessed as “very good” when thetip was in a completely or nearly unchanged position, and as “good” whenthe tip was between the middle and the end of the base. Threading wasdetermined qualitatively by applying a little adhesive by means of acartridge pistol to a piece of cardboard secured to a wall, thecartridge pistol was pulled away from the adhesive applied at the end ofapplication by pulling it back rapidly, and the length of the threadwhich remained at the severance point was measured.

A measure employed for the open time was the skin formation time(“tack-free time”). The skin formation time was determined as describedin example 1.

A measure employed for the curing rate was the time until the adhesivehad cured through. The time until through-curing was studied by applyingthe adhesive by means of a cartridge pistol through a round tip (opening10 mm) as a horizontal, free-hanging cone with a length of approx. 50 mmand a thickness in the middle of 30 mm to a piece of cardboard securedto a wall, left under standard climatic conditions over 7 days, then cutvertically down the middle, and the thickness of the cured adhesivelayer was measured with a ruler.

To determine the mechanical properties after the curing, the Shore Ahardness, the tensile strength, the elongation at break and theextension stress were measured at 100%. The Shore A hardness wasdetermined to DIN 53505 on specimens cured under standard climaticconditions over 14 days. To test the further mechanical properties, theadhesive, 2 hours after the production, was pressed by means of a pressto a film of thickness approx. 2 mm, and the film was cured understandard climatic conditions over 14 days, and tested to DIN EN 53504for tensile strength, elongation at break and extension stress at 100%(pulling speed: 200 mm/min).

All adhesives cured fully without bubbles.

The results of the tests are listed in table 6.

TABLE 6 Properties of the elastic adhesives of examples 12 to 15 and ofcomparative examples 16 to 18. Example 16 17 18 12 13 14 15 (comp.)(comp.) (comp.) Sagging very very very very very very good good goodgood good good good Threading (cm) 10 8 4 5 10 4 4 Skin formation time105 280 180 100 55 60 65 (min) Through-curing (mm) 9 8 8 8 11 10 4 ShoreA hardness 38 42 34 31 39 37 31 Tensile strength (MPa) 2.1 2.1 1.4 1.72.1 1.9 1.8 Elongation at break (%) 1350 1070 1010 1040 1140 1310 1040Extension stress at 1.00 1.46 0.93 1.01 1.39 1.04 1.44 100% (MPa)

Example 19 and Comparative Examples 20 to 21 One-Component ElasticSealants

For each example, the particular constituents according to table 7 inthe parts by weight specified were processed without preceding drying ina vacuum mixer with exclusion of moisture to give a homogeneous paste,which was immediately transferred into an internally coated aluminumcartridge which was sealed airtight.

The polyurethane polymer PUP-4 was prepared as follows:

1190 g of polyoxypropylenediol (Acclaim® 4200 N, Bayer; OH number 28.1mg KOH/g), 620 g of polyoxypropylenepolyoxyethylenetriol (Caradol®MD34-02, Shell; OH number 35.0 mg KOH/g) and 190 g of 2,4-tolylenedilsocyanate (Scuranate® T-100, Lyondell) were converted at 80° C. to anNCO-terminated polyurethane polymer with a content of free isocyanategroups determined by titrimetric means of 2.32% by weight and aviscosity at 20° C. of 5 Pa·s. The thickener was prepared as describedin example 12.

The ratio between the isocyanate groups and the aldimino groups for allexamples is 1.0/0.67.

TABLE 7 Composition of the one-component elastic sealants of examples 19and of comparative examples 20 to 21. Example 20 21 19 (comparative)(comparative) Polyurethane polymer PUP-4 24.0 24.0 24.0 Dialdimine A-1,A-7, A-8, 3.26 3.47 3.56 Plasticizer^(a) 1.74 1.53 1.44 Chalk 38.0 38.038.0 Thickener 28.0 28.0 28.0 Titanium dioxide 4.5 4.5 4.5Epoxysilane^(b) 0.2 0.2 0.2 Acid catalyst^(c) 0.3 0.3 0.3 ^(a)Diisodecylphthalate (DIDP; Palatinol ® Z, BASF).^(b)3-Glycidoxypropyltri-ethoxysilane (Dynasylan ® GLYEO, Degussa).^(c)Salicylic acid (5% by weight in dioctyl adipate).

The one-component elastic sealants thus obtained were tested forapplication properties (sagging, threading), open time (skin formationtime), curing rate (through-curing) and mechanical properties aftercuring (Shore A hardness, tensile strength, elongation at break,extension stress at 100%) were tested as described for example 12.

In addition, the sealants were tested qualitatively for tack. This wasdone by, one day or 3 days after the application thereof, pressing thecured Shore A specimens with the thumb and then determining how long thespecimen remained adhering on the thumb as the hand was raised. The tackwas then assessed as high (specimen remains adhering for more than 3seconds), medium (specimen remains adhering for about 3 seconds), low(specimen remains adhering for 1 to 2 seconds) and none (specimenremains adhering for less than 1 second).

All sealants cured completely without bubbles.

The results of the tests are listed in table 8.

TABLE 8 Properties of the one-component elastic adhesives of example 19and of comparative examples 20 to 21. Example 20 21 19 (comparative)(comparative) Sagging very good very good very good Threading (cm) 5 4 8Skin formation time (min) 250 95 70 Through-curing (mm) 8 7 3 Shore Ahardness 30 32 23 Tensile strength (MPa) 2.0 2.0 1.4 Elongation at break(%) 1180 1150 1200 Extension stress at 100% 0.35 0.42 0.34 (MPa) Tackafter 1 day low low high Tack after 3 days none none medium

Examples 22 to 23 and Comparative Example 24 Two-Component ElasticAdhesives

For each example, component K1 was prepared as follows:

In a planetary mixer, under a nitrogen atmosphere, 200 g of partlycarbodiimidated 4,4′-methylenediphenyl diisocyanate (Desmodur® CD,Bayer; NCO content=29.5% by weight) were mixed with 280 g ofpolyurethane polymer PUP-1 and 20 g of hydrophobic fumed silica(Aerosil® R972, Degussa) to give a homogenous paste, and transferredinto cartridges.

Subsequently, component K2 according to table 9 was weighed in the partsby weight specified without preceding drying into a polypropylenecartridge and mixed by means of a centrifugal mixer (SpeedMixer™ DAC150, FlackTek Inc.; 2 min. at 3000 rpm) to give a homogeneous paste. Tothis end, the parts by weight of component K1 specified in table 9 wereadded and mixed in immediately (30 sec at 3000 rpm).

The polyurethane polymer PUP-1 was prepared as described in example 1.The thickener was prepared as described in example 12.

The ratio between the isocyanate groups of component K1 and the sum ofthe reactive groups (hydroxyl groups, primary amino groups and aldiminogroups) of component K2 is always 0.91/1. The ratio between the waterand the aldimino groups in component K2 is always 0.6/1.

TABLE 9 Composition of the two-component elastic adhesives of examples22 to 23 and of comparative example 24. Example 24 22 23 (comparative)Component K1 18.2 18.7 18.4 Component K2: Polyol^(a) 47.0 47.0 47.0Dialdimine A-1 A-2 A-9 4.7 4.7 4.7 Diamine^(b) 1.0 1.0 1.0 Thickener10.0 10.0 10.0 Amine catalyst^(c) 0.1 0.1 0.1 Acid catalyst^(d) 0.2 0.20.2 Water 0.139 0.153 0.145 Molecular sieve^(e) 2.0 2.0 2.0 Chalk 35.035.0 35.0 ^(a)Low monool polyoxypropylenepolyoxyethylenediol (Preminol ®S-X5006, Asahi Glass; OH number 28.0 mg KOH/g). ^(b)1,3-xylylenediamine.^(c)DABCO ® 33-LV, Air Products. ^(d)Salicylic acid (5% by weight indioctyl adipate). ^(e)8 Å molecular sieve (Purmol ® 13, Zeochem Europe).

The two-component elastic adhesives thus obtained were appliedimmediately after the mixing of the two components and tested for opentime, curing rate and mechanical properties after curing.

A measure employed for the open time was the tack-free time of theadhesive. This test was effected analogously to the determination of theskin formation time as described for example 1.

A measure employed for the curing rate was the curing time. To determinethe curing time, the Shore A hardness (measured to DIN 53505) wasmeasured on the cured adhesive at regular intervals and the adhesive wasassessed as being completely cured as soon as the value for the Shore Ahardness remained virtually constant.

To determine the mechanical properties after curing, the Shore Ahardness, the tensile strength, the elongation at break and the modulusof elasticity were measured. The Shore A hardness was determined to DIN53505 on specimens which had been cured under standard climaticconditions over 4 days. To test the further mechanical properties, theadhesive, immediately after the production, was pressed by means of apress to a film of thickness approx. 2 mm, and the film was cured understandard climatic conditions over 4 days and tested to DIN EN 53504 fortensile strength, elongation at break and modulus of elasticity (pullingspeed: 200 mm/min).

All adhesives cure completely without bubbles.

The results of the tests are listed in table 10.

TABLE 10 Properties of the two-component elastic adhesives of examples22 and 23 and of comparative example 24. Example 24 22 23 (comparative)Tack-free time (min) 120 105 45 Curing time (h) 12 11 9 Shore A hardness47 46 49 Tensile strength (MPa) 2.4 2.0 2.3 Elongation at break (%) 600600 610 Modulus of elasticity at 0.5-5% 2.4 2.1 2.3 extension (MPa)

It is clear from the examples that the inventive compositions, with acomparable curing rate, have a significantly longer open time than thecompositions of the comparative examples. In the further propertiesdetermined in each case, such as the storage stability, the applicationproperties, the mechanical properties after curing or the tack, incontrast, no significant differences are found between the inventivecompositions and the compositions of the comparative examples.

1. A composition comprising a) at least one polyisocyanate P havingaromatic isocyanate groups, and b) at least one dialdimine A of theformula (I),

wherein X is the radical of a diamine DA with two primary amino groupsafter the removal of these two amino groups; and Y¹ and Y² are eithereach independently a monovalent hydrocarbon radical having 1 to 12carbon atoms, or together are a divalent hydrocarbon radical which has 4to 20 carbon atoms; and Y³ is a monovalent hydrocarbon radical or is amonovalent hydrocarbon radical having at least one heteroatom; with theproviso that at least one of the two primary amino groups of the diamineDA is an aliphatic amino group, and the two primary amino groups of thediamine DA differ from one another either in the number of hydrogenatoms on the carbon atoms (Ca) in the a position to the particular aminogroup by at least one Or in the number of hydrogen atoms on the carbonatoms (Cb) in the b position to the particular amino group by at leasttwo.
 2. The composition as claimed in claim 1, wherein the diamine DA isselected from the group consisting of 1,2-propanediamine, 2methyl-1,2-propanediamine, 1,3-butanediamine, 1,3-diaminopentane (DAMP),4-aminoethylaniline, 4-aminomethylaniline,4-[(4-aminocyclohexyl)methyl]aniline, 2-aminoethylaniline,2-aminomethylaniline, 2-[(4-aminocyclohexyl)methyl]aniline,4-[(2-aminocyclohexyl)methyl]aniline;2,2,4-trimethylhexamethylenediamine (TMD),1,5-diamino-2-butyl-2-ethyl-pentane,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(=isophoronediamine=IPDA) and 1,4-diamino-2,2,6-trimethylcyclohexane(TMCDA).
 3. The composition as claimed in claim 1, wherein thepolyisocyanate P having aromatic isocyanate groups is a polyurethanepolymer PUP having aromatic isocyanate groups.
 4. The composition asclaimed in claim 3, wherein the polyisocyanate used for the preparationof the polyurethane polymer PUP having aromatic isocyanate groups is anaromatic polyisocyanate which is selected from the group consisting of2,4- and 2,6-tolylene diisocyanate and any desired mixtures of theseisomers (TDI), 4,4′-, 2,4′- and 2,2′-diphenylmethane diisocyanate andany desired mixtures of these isomers (MDI), mixtures of MDI and MDIhomologs (polymeric MDI or PMDI), 1,3- and 1,4-phenylene diisocyanate,2,3,5,6-tetramethyl-1,4-thisocyanatobenzene, naphthalene1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODI),dianisidine diisocyanate (DADI), oligomers and polymers of theaforementioned isocyanates, and any desired mixtures of theaforementioned isocyanates.
 5. The composition as claimed in claim 1,wherein the polyisocyanate P having aromatic isocyanate groups is anaromatic polyisocyanate PI which is selected from the group consistingof 2,4- and 2,6-tolylene diisocyanate and any desired mixtures of theseisomers (TDI), 4,4′-, 2,4′- and 2,2′-diphenylmethane diisocyanate andany desired mixtures of these isomers (MDI), mixtures of MDI and MDIhomologs (polymeric MDI or PMDI), 1,3- and 1,4-phenylene diisocyanate,2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene1,5-diisocyanate (NDI), 3,3′-dimethyl-4,4′-diisocyanatodiphenyl (TODI),dianisidine diisocyanate (DADI), oligomers and polymers of theaforementioned isocyanates, and any desired mixtures of theaforementioned isocyanates.
 6. The composition as claimed in claim 1,wherein the diamine DA is selected from the group consisting of1,3-diaminopentane (DAMP), 1,5-diamino-2-butyl-2-ethylpentane,2,2,4-trimethylhexamethylenediamine (TMD) and1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(=isophoronediamine=IPDA).
 7. The composition as claimed in claim 1,wherein Y³ is a radical of the formula (II) or (III),

where R³ is a hydrogen atom or an alkyl or arylalkyl group; R⁴ is ahydrocarbon radical having 1 to 30 carbon atoms; and R⁵ is a hydrogenatom or is a linear or branched alkyl radical having 1 to 30 carbonatoms, or is a mono- or polyunsaturated, linear or branched hydrocarbonradical having 5 to 30 carbon atoms, or is a substituted aromatic orheteroaromatic 5- or 6-membered ring.
 8. The composition as claimed inclaim 1, wherein Y¹ and Y² are each methyl.
 9. The composition asclaimed in claim 1, wherein the polyisocyanate P is present in an amountof 5 to 95% by weight based on the overall composition.
 10. Thecomposition as claimed in claim 1, wherein the dialdimine A of theformula (I) is present in the composition in such an amount that theratio between the number of the aldimino groups and the number of theisocyanate groups in the composition is 0.1 to 1.1.
 11. The compositionas claimed in claim 1, wherein the composition comprises at least onecatalyst, especially a catalyst which accelerates the hydrolysis of thealdimines.
 12. The composition as claimed in claim 1, wherein thecomposition has one component.
 13. The composition as claimed in claim1, wherein the composition has two components and consists of acomponent K1 and a component K2.
 14. The composition as claimed in claim13, wherein the polyisocyanate P having aromatic isocyanate groups andthe dialdimine A of the formula (I) is part of component K1, andcomponent K2 comprises compounds reactive toward isocyanate groups. 15.The composition as claimed in claim 13, wherein the polyisocyanate Phaving aromatic isocyanate groups is part of component K1 and componentK2 comprises the dialdimine A of the formula (I) and compounds reactivetoward isocyanate groups.
 16. A cured composition which is obtained bythe reaction of a composition as claimed in claim 1 with water.
 17. Acured composition which is obtained by the mixing of the two componentsK1 and K2 of a composition as claimed in claim 13, if followed by areaction with water.
 18. A process for adhesive bonding of a substrateS1 to a substrate S2, comprising the steps of i) applying a compositionas claimed in claim 1 to a substrate S1; ii) contacting the compositionapplied with a substrate S2 within the open time of the composition; ori′) applying a composition as claimed in claim 1 to a substrate S1 andto a substrate S2; ii′) contacting the compositions applied with oneanother within the open time of the composition; said substrate S2consisting of the same material as, or a different material than, thesubstrate S1.
 19. A process for sealing, comprising the step of i″)applying a composition as claimed in claim 1 between a substrate S1 anda substrate S2, such that the composition is in contact with thesubstrate S1 and the substrate S2; said substrate S2 consisting of thesame material as, or a different material than, the substrate S1.
 20. Aprocess for coating a substrate S1, comprising the step of i′″) applyinga composition as claimed in claim 1 to a substrate S1 within the opentime of the composition.
 21. The process as claimed in claim 18, whereinthe substrate S1 and/or the substrate S2 has been pretreated before theadhesive bonding or sealing or coating.
 22. The process as claimed inclaim 18, wherein the substrate S1 and/or the substrate S2 is aninorganic substrate or natural stone; an organic substrate, a plastic; acoated substrate; or a paint or a coating.
 23. An article which has beenadhesive bonded, sealed or coated by a process as claimed in claim 20.24. The article as claimed in claim 23, wherein the article is a builtstructure or an industrial good or a consumer good or a mode oftransport or an installable component of a mode of transport.
 25. Thecomposition as claimed in claim 1, wherein the at least one heteroatomof Y³ is an oxygen atom.
 26. The composition as claimed in claim 25,wherein the oxygen is in the form of ether, carbonyl or ester groups.27. The composition as claimed in claim 1, wherein the at least onedialdimine A of formula (I) is obtained by a condensation reaction withelimination of water between at least one diamine DA of formula (IV):

and at least one aldehyde ALD of formula (V):

wherein X, Y¹, Y² and Y³ have the same definitions recited in claim 1,and wherein the diamine DA is selected from the group consisting of1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1,3-diaminopentane,1,5-diamino-2-butyl-2-ethyl-pentane,2,2,4-trimethylhexamethylenediamine, and 4-aminomethylaniline, and theat least one polyisocyanate P having aromatic isocyanate groups isselected from the group consisting of 4,4′-methylenediphenyldiisocyanate and tolylene diisocyanate.
 28. The composition as claimedin claim 27, wherein the at least one aldehyde ALD is2,2-dimethyl-3-lauroyloxypropanal.